1. Field of the Invention
This invention relates to the improved design of rubber dam clamps, and more particularly to improved rubber dam clamps that retain the rubber dam in the mouth of a patient during the course of dental treatment, through the use of friction and/or adhesives.
2. Prior Art
Rubber dam clamps are commonly known in the prior art of dentistry as devices designed to apply reciprocal mechanical forces to the sides of a tooth in order to be mechanically retained in position on that tooth to restrain a rubber dam membrane. The rubber dam, is known in the prior art of dentistry as an elastic membrane designed to isolate the dentist's operative work site from the oral environment during treatment. The rubber dam is stretched over rubber dam clamps in order to be retained in position by them during treatment. The prior art of rubber dam retentive clamps is exclusively composed of mechanically retained clamps which reciprocally engage the facial and lingual surfaces of teeth, below the height of curvature of the tooth in the infra-bulge area in order to gain retention both laterally and vertically. The clamps which are widely marketed and accepted as the predominant prior art clamp are almost exclusively composed of resilient stainless steel tempered metal and are reuseable. Alternatively, rubber dam clamps manufactured of resilient plastic or composite material for repetitive or one-time use have been introduced. Despite the introduction of new materials for their construction, all true rubber dam clamps in the prior art are simple, mechanically retained devices.
One of the disadvantages and shortcomings of prior art rubber dam clamps is that they are not always stable on the tooth because they are simple mechanical devices that only approximate the contours of teeth, which vary widely in size and anatomical configuration. Prior art rubber dam clamps very often shift in position during a dental procedure, pinching the patient's gums and completely dislodge, causing the rubber dam to fail during application. When this happens, the frustrating and time-consuming task of stopping the procedure, re-applying the rubber dam clamp, and stretching the rubber dam over the clamp and an external frame must take place before resuming the operative procedure. Prior art rubber dam clamps may also be vertically unstable and are prone to rotation and tipping about an axis due to the design of their clasping components. In addition to the disadvantages of painful impingement on the patient's gums, the sharp metal clasps which contact the tooth either on enamel or cementum, the exposed dentine on the root surface, have been known to leave scratch marks or defects which later can be the focus for plaque accumulation and subsequent decay.
The prior art of rubber dam clamps is composed of simple, mechanically retained clamps that engage the tooth on the lingual and facial surfaces below the height of curvature in a region known in the dental art as the infra-bulge area. Further, U.S. Pat. No. 6,093,022, entitled Dental Dam With Integral Clamp, issued to Steven T. Swallow, Jul. 25, 2000, is the only known prior art reference to the adhesive retention of a rubber dam. The device of this disclosure is not of a true clamp, which is a separate device from a rubber dam, but rather a rubber dam with elastic projections coated with adhesive. Not only does the disclosure fail to describe a device separate from a rubber dam, there is also no true reciprocal mechanism to apply reciprocal forces in a clamping action in order to grasp an object, the tooth in this instance, in order to hold itself in position. The projections on the rubber dam, not reciprocally linked to apply tension, are simply a way of increasing and orienting surface areas of the rubber dam membrane in order to cement it directly to a tooth. Therefore, the prior art device would more appropriately be described as a rubber dam improvement.
U.S. Pat. No. 4,986,752, issued Jan. 22, 1991, to R. Gary Graves, entitled Cushioned Clamp for Securing a Dental Dam, describes a device which is a cushion composed of an elastomeric material with a slot-like recess which covers the metal clasps of a rubber dam clamp so that a portion of the cushion is compressed between the inside edge of the clamp and the tooth engaged during an application. The device is said to secure a rubber dam clamp, but makes no mention to the use of dentally compatible adhesives in order to increase retention and to stabilize the clamp during an application. In addition, the cushion, when in place, contacts a tooth in precisely the same manner in which any mechanical clamp is designed, which is to apply reciprocal forces laterally to the tooth below the height of curvature in the infra-bulge area for retention. Clamps apply retentive forces exclusively in the infra-bulge area. This results in vector forces in a cervical direction which deflect the clasps of the clamp cervically against the gingival tissues, consequently causing impingement and pain to the patient. The device is said to increase patient comfort, because the steel of the rubber dam clamp does not contact the gingival or root surface. The disclosure states “The dentist does not have to be concerned about the rubber dam clamp slipping further gingivally, . . . causing . . . the clamp to impinge on an anaesthetized gingival or cementum . . . ”. The claim that a patient's comfort is increased for this reason is not accurate in that the rubber dam clamp, even with the cushion applied, is still forced against the gum tissue by reciprocal forces of the clamp deflected in a cervical direction by the inclined slope of the infra-bulge contours of the tooth. Thus the tendency for the clamp to impinge on the gingival is still present in this device. The device described in this disclosure makes no mention of the use of adhesives as a means to increase retention and stability of the clamp and to prevent the clamp from being cervically deflected and prevent impingement of the gingival tissues.
Thus a need exists for an improved rubber dam clamp that is retained by both frictional forces and adhesives in order to increase the retention and stability of the clamp during rubber dam applications.